6. The emergence of the railroad during the 1800' s done(-did) much to accelerate the settlement of the midwestern United States

7. The adder is a snake (+which/that) has a relatively stout body, a short tail, and a flat head.

8. By working in television, on the legitimate stage, and in the concert hall, Producer Ellis Haizli's versatility was proven(-Producer Ellis Haizlip proven his versatility)

9. The curative effect of smoke in the leather tanning process was probably an early discover(-discovery).

10. Advertising fall(-falls) into two main categories: consumer advertising and trade advertising.

11. Acquire(-Acquiring) education is the principal way of gaining status in a culture that generally stresses achievement, skillfulness, and upward mobility.

12. The Medal of Honor is the highest military award for courage, being(-that can be) given to any individual in the United States.

13. The question of the origin of the Moon is interested(-interesting) not only in itself but also as a part of the larger genesis of the Earth and the solar system.

14. Fifty-eight years after novelist Richard Wright left his home in Mississippi, the state had(削除） proclaimed November 21-28 as Richard Wright Week.

15. The full Security Council approved a resolution to ensure Syrian compliance on chemical weapons, and the group responsible for destroying those weapons announced a timetable that start(-starts) on Tuesday.

16. Aluminum, considered a common metal, is used industrial(-industrially) in significant quantities.

17. A metropolitan region is defined as a central city and the territory where(-which) surrounds it.